You don’t seem to understand that games don’t release by themselves, as TTG games don’t fix and patches by themselves.
There need to be work done to do so. People need to do this which first has to be approved.
We are talking about a nearly 6 year old game. Those don’t sell like hot cakes after that time you must know.
In fact DF exactly knows how much their games sell and if they aren’t selling dozens on Steam every week they will sell even a lot less on other PC platforms.
So, did you already mail that pile of money to them?
(btw. to be precise: No. It sounds exactly the same.)
I don’t know if their app is shitty. The requirement to need one is though.
It’s not. Well OK, it is. But the content you can get/buy on itch().io can contain anything the creator likes, including DRM.